It is known that people with orthopedic problems of the knee joints and other joints such as the ankle or elbow, require an orthopedic brace or orthoses especially in cases of injury or post-operative trauma. Braces and orthoses provide a hinged constraint between the femur and the tibia or other lever joint parts in order to support stresses which would otherwise be damaging to the human joint itself.
In general, the function of an orthoses is to immobilise or restrict the movement of a joint affected by trauma, arthrosis, sprained ligaments or which have undergone surgery.
Another use of braces is functional rehabilitation or re-education, where the brace can be used to reduce the load on a joint and lessen the pain, or used for preventive purposes in cases of osteoporosis or bone fragility.
Braces usually consist of a rigid or soft framework enclosing the limb and are designed to guarantee adequate harnessing of the joint and prevent the onset of strain on the ligaments and synovial membranes when the injured or convalescent subject is walking.
According to the background art, in the specific case of the knee, the frame of the knee brace comprises means of constraint for the femur and the tibia in areas close to the knee and a structure connecting these means with a jointed hinge positioned at the level of the knee. The means of constraint usually consist of half-rings, fixed with suitable straps, encircling both the femur and the tibia of the injured subject or bands, belts or sleeves made from woven material which create a constraint between the ends of the mechanical joint and the limb.
In an example application of the orthoses to the leg, the mechanical joint is positioned to the side of the femur and tibia. The orthoses has multiple centres of rotation and a configuration with four pivots to faithfully reproduce the kinematics of the human limb.
In order to ensure sufficient freedom of movement for the limb and the correct amount of mobility, the frame is positioned almost entirely along the sides of the joint such as the knee or the elbow.
The presence of four pivots on the joint considerably reduces the risk of the knee brace moving and slipping downwards.
It is also known that each subject needs different degrees of angular freedom depending on the type of injury involved. This is why braces have been developed with means for adjusting and limiting the range of angular freedom.
Traditional joints for knee braces with an adjustable angular range generally comprise a platform fitted with at least one pair of hinge couplings for the respective uprights, fitted with means for restraining the joint in question, in which the platform comprises a central shaped plate and at least one location for an extractable insert which abuts against the plate and at least one end of an upright.
The joint also comprises means of temporary restraint for the inserts with the purpose of limiting the movement of the joint during extension and/or flexion. In order to be able to adjust the range of motion (R.O.M.) in the various possible angular configurations, the insert for limiting flexion and extension must be interchangeable with inserts having different profiles.
The shape of the inserts is such as to limit the reciprocal angular range between the uprights connected to the joint, the shape differing in order to obtain different angular ranges depending on the needs dictated by patient's pathology.
According to the known solutions, the joint presents internal seats for the inserts, consisting of accessible slots formed inside the platform. At the level of each slot, the base surface of the platform presents an opening designed to make the seat of the corresponding insert visible.
While these solutions solve the problems concerning the range of motion (R.O.M.) adjustment system of orthopedic braces with angular range, they do however present other problems which will be described below.
First and foremost, the traditional insert system makes use of components of a relatively large size, creating a first difficulty in the use of the brace due to the considerable thickness of each hinge. The adjustment system is also difficult to use because of the limited stability of the inserts and because of the difficulty in changing the inserts when it is necessary to vary the range.
In general, the traditional joints for orthoses use bulky, heavy components which make them complicated and costly to construct for the manufacturer.
Recently there have been attempts to lighten and simplify orthoses with traditional joints in order to increase their performance. However, they continue to constitute an encumbrance involving practical difficulties for the user due to their excessive weight and size, both factors limiting user comfort.